Let me explain clearly. There is, for example, the class "chair" that we use to describe a certain group of compound objects that we call "chairs." But what do these chairs have in common? Their function. There might be wooden chairs, metal chairs, stone chairs, glass chairs, and so on. There are so many different chairs, and this means that there are many different classes of chair objects. But what is the head class? What is the one class, from which all chair objects are descendants?

Is there such a object? Yes there is. Is this head object real? Can we touch it? The answer may look simple, but it is not that simple. Think, dear reader, look around, and see if you can find such an object. The answer to your quest and the question will come later in the text.

For now we can decide that all these objects belong in classes. I mean every head/primary object, every head/primary definition of such an object allows for the possibility of creating a class.

A head/primary definition is composed out of the minimum characteristics/properties that an object has to have to belong to that class, a bit like object classes in object-oriented programming. Notice that I wrote head/primary object and head/primary definition. Do they then not mean the same? Well, they don't.

The head/primary object is the physical object that all objects of that class have in common.

The head/primary definition is the definition they all have in common.

This might look the same, but that is often not the case. The question is, are "objects" only objects we can see and touch, or are there different types of objects, existent and non-existent objects?

Fro example, are there real chairs and imagined chairs, and do both belong in the main class of "chairs"? Is the fact that they are real or imaginary a property of those objects, or a separate object class? Intriguing question, is it not?

Now let's have a look at this, try to figure it out using an example.

The head/primary object "airplane" and the head/primary definition of "airplane" are not the same. The head/primary definition could be: "a winged craft that can fly." Every single aircraft has this definition in common. But finding a head/primary object "airplane" is much more difficult. There is one, but it is not specific for aircraft only. There is an object all aircraft have in common. But more likely that what they have in common is a collection of singular objects.

What is a collection ? A collection is a group of objects, which might have several things, or just one property, in common. For example, there could be a collection of neutrons, which have in common that they are neutrons, but might be thousands of miles a part from each other.

Looking Closer